<title>安慰奶牛</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstring&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;iostream&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;algorithm&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
 
<span class="pl-k">struct</span> <span class="pl-n">Edge</span>
<span class="pl-p">{</span>
	<span class="pl-kt">int</span> <span class="pl-n">x</span><span class="pl-p">;</span>
	<span class="pl-kt">int</span> <span class="pl-n">y</span><span class="pl-p">;</span>
	<span class="pl-kt">int</span> <span class="pl-n">cost</span><span class="pl-p">;</span>
<span class="pl-p">}</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-mi">100001</span><span class="pl-p">];</span>
<span class="pl-kt">int</span> <span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-mi">100001</span><span class="pl-p">];</span>
<span class="pl-kt">int</span> <span class="pl-n">val</span><span class="pl-p">[</span><span class="pl-mi">100001</span><span class="pl-p">];</span>
<span class="pl-kr">inline</span> <span class="pl-kt">int</span> <span class="pl-nf">find</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">x</span><span class="pl-p">)</span>           
<span class="pl-p">{</span>
    <span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-p">,</span><span class="pl-n">j</span><span class="pl-p">,</span><span class="pl-n">r</span><span class="pl-p">;</span>
    <span class="pl-n">r</span><span class="pl-o">=</span><span class="pl-n">x</span><span class="pl-p">;</span>
    <span class="pl-k">while</span><span class="pl-p">(</span><span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">r</span><span class="pl-p">]</span><span class="pl-o">!=</span><span class="pl-n">r</span><span class="pl-p">)</span> 
        <span class="pl-n">r</span><span class="pl-o">=</span><span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">r</span><span class="pl-p">];</span>
    <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-n">x</span><span class="pl-p">;</span>
    <span class="pl-k">while</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-o">!=</span><span class="pl-n">r</span><span class="pl-p">)</span> 
    <span class="pl-p">{</span>
        <span class="pl-n">j</span><span class="pl-o">=</span><span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">];</span>
        <span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">r</span><span class="pl-p">;</span>
        <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-n">j</span><span class="pl-p">;</span>
    <span class="pl-p">}</span>
    <span class="pl-k">return</span> <span class="pl-n">r</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
<span class="pl-kr">inline</span> <span class="pl-kt">void</span> <span class="pl-nf">merge</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">x</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">y</span><span class="pl-p">)</span>
<span class="pl-p">{</span>
    <span class="pl-kt">int</span> <span class="pl-n">t</span><span class="pl-o">=</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">x</span><span class="pl-p">);</span>
    <span class="pl-kt">int</span> <span class="pl-n">h</span><span class="pl-o">=</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">y</span><span class="pl-p">);</span>
    <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">t</span><span class="pl-o">&lt;</span><span class="pl-n">h</span><span class="pl-p">)</span>
        <span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">h</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">t</span><span class="pl-p">;</span>
    <span class="pl-k">else</span>
        <span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">t</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">h</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
 
<span class="pl-kt">bool</span> <span class="pl-nf">cmp</span><span class="pl-p">(</span><span class="pl-k">const</span> <span class="pl-n">Edge</span><span class="pl-o">&amp;</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-k">const</span> <span class="pl-n">Edge</span><span class="pl-o">&amp;</span> <span class="pl-n">b</span><span class="pl-p">)</span>
<span class="pl-p">{</span>
	<span class="pl-k">return</span> <span class="pl-n">a</span><span class="pl-p">.</span><span class="pl-n">cost</span><span class="pl-o">&lt;</span><span class="pl-n">b</span><span class="pl-p">.</span><span class="pl-n">cost</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
 
<span class="pl-kt">void</span> <span class="pl-nf">init</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">)</span>           
<span class="pl-p">{</span>
	<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">n</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
		<span class="pl-n">set</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">i</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">kruskal</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">m</span><span class="pl-p">)</span>
<span class="pl-p">{</span>
	<span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-p">,</span><span class="pl-n">num</span><span class="pl-p">,</span><span class="pl-n">sum</span><span class="pl-p">,</span><span class="pl-n">from</span><span class="pl-p">,</span><span class="pl-n">to</span><span class="pl-p">;</span>
	<span class="pl-n">sort</span><span class="pl-p">(</span><span class="pl-n">edge</span><span class="pl-p">,</span><span class="pl-n">edge</span><span class="pl-o">+</span><span class="pl-n">m</span><span class="pl-p">,</span><span class="pl-n">cmp</span><span class="pl-p">);</span>
	<span class="pl-n">sum</span><span class="pl-o">=</span><span class="pl-n">num</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span>
	<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">m</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
	<span class="pl-p">{</span>
		<span class="pl-n">from</span> <span class="pl-o">=</span> <span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">x</span><span class="pl-p">);</span>     
		<span class="pl-n">to</span> <span class="pl-o">=</span> <span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">y</span><span class="pl-p">);</span>      
		<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">from</span> <span class="pl-o">!=</span> <span class="pl-n">to</span><span class="pl-p">)</span>        
		<span class="pl-p">{</span>
			<span class="pl-n">merge</span><span class="pl-p">(</span><span class="pl-n">from</span><span class="pl-p">,</span><span class="pl-n">to</span><span class="pl-p">);</span>    
			<span class="pl-n">sum</span><span class="pl-o">+=</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">cost</span><span class="pl-p">;</span>
			<span class="pl-n">num</span><span class="pl-o">++</span><span class="pl-p">;</span>
		<span class="pl-p">}</span>
		<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">num</span><span class="pl-o">==</span><span class="pl-n">n</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">)</span>
			<span class="pl-k">break</span><span class="pl-p">;</span>
	<span class="pl-p">}</span>
	<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">num</span><span class="pl-o">&lt;</span><span class="pl-n">n</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">)</span>
		<span class="pl-k">return</span> <span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">;</span>
	<span class="pl-k">else</span>
		<span class="pl-k">return</span> <span class="pl-n">sum</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
 
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">()</span>
<span class="pl-p">{</span>
	<span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-p">,</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-n">m</span><span class="pl-p">,</span><span class="pl-n">k</span><span class="pl-p">;</span>
	<span class="pl-kt">int</span> <span class="pl-n">minn</span><span class="pl-o">=</span><span class="pl-mh">0x3f3f3f3f</span><span class="pl-p">;</span>
	<span class="pl-n">memset</span><span class="pl-p">(</span><span class="pl-n">val</span><span class="pl-p">,</span><span class="pl-mi">0</span><span class="pl-p">,</span><span class="pl-k">sizeof</span><span class="pl-p">(</span><span class="pl-n">val</span><span class="pl-p">));</span>
	<span class="pl-k">while</span><span class="pl-p">(</span><span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">m</span><span class="pl-p">)</span><span class="pl-o">!=</span><span class="pl-n">EOF</span><span class="pl-p">)</span>
	<span class="pl-p">{</span>
		<span class="pl-n">init</span><span class="pl-p">(</span><span class="pl-n">n</span><span class="pl-p">);</span>
		<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">n</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
		<span class="pl-p">{</span>
			<span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">val</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]);</span>
			<span class="pl-n">minn</span><span class="pl-o">=</span><span class="pl-n">min</span><span class="pl-p">(</span><span class="pl-n">minn</span><span class="pl-p">,</span><span class="pl-n">val</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]);</span>
		<span class="pl-p">}</span>     
		<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">m</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
		<span class="pl-p">{</span>
			<span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">x</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">y</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">cost</span><span class="pl-p">);</span>
			<span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">cost</span><span class="pl-o">+=</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">cost</span><span class="pl-p">;</span>
			<span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">cost</span><span class="pl-o">+=</span><span class="pl-n">val</span><span class="pl-p">[</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">x</span><span class="pl-p">]</span><span class="pl-o">+</span><span class="pl-n">val</span><span class="pl-p">[</span><span class="pl-n">edge</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">y</span><span class="pl-p">];</span> 
		<span class="pl-p">}</span>
		<span class="pl-n">k</span><span class="pl-o">=</span><span class="pl-n">kruskal</span><span class="pl-p">(</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-n">m</span><span class="pl-p">)</span><span class="pl-o">+</span><span class="pl-n">minn</span><span class="pl-p">;</span>
		<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">k</span><span class="pl-o">==-</span><span class="pl-mi">1</span><span class="pl-p">)</span>
			<span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;no</span><span class="pl-se">\n</span><span class="pl-s">&quot;</span><span class="pl-p">);</span>
		<span class="pl-k">else</span>
			<span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d</span><span class="pl-se">\n</span><span class="pl-s">&quot;</span><span class="pl-p">,</span><span class="pl-n">k</span><span class="pl-p">);</span>
	<span class="pl-p">}</span>
<span class="pl-p">}</span>
</cpde></pre></div>